Electro-chemical deposition system

ABSTRACT

The present invention provides an electro-chemical deposition system that is designed with a flexible architecture that is expandable to accommodate future designs and gap fill requirements and provides satisfactory throughput to meet the demands of other processing systems. The electro-chemical deposition system generally comprises a mainframe having a mainframe wafer transfer robot, a loading station disposed in connection with the mainframe, one or more processing cells disposed in connection with the mainframe, and an electrolyte supply fluidly connected to the one or more electrical processing cells. Preferably, the electro-chemical deposition system includes an edge bead removal/spin-rinse-dry (EBR/SRD) station disposed on the mainframe adjacent the loading station, a rapid thermal anneal chamber attached to the loading station, a seed layer repair station disposed on the mainframe, and a system controller for controlling the electro-chemical deposition process and the components of the electro-chemical deposition system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to deposition of a metal layeronto a wafer/substrate. More particularly, the present invention relatesto an electro-chemical deposition or electroplating system for forming ametal layer on a wafer/substrate.

2. Background of the Related Art

Sub-quarter micron, multi-level metallization is one of the keytechnologies for the next generation of ultra large scale integration(ULSI). The multilevel interconnects that lie at the heart of thistechnology require planarization of interconnect features formed in highaspect ratio apertures, including contacts, vias, lines and otherfeatures. Reliable formation of these interconnect features is veryimportant to the success of ULSI and to the continued effort to increasecircuit density and quality on individual substrates and die.

As circuit densities increase, the widths of vias, contacts and otherfeatures, as well as the dielectric materials between them, decrease toless than 250 nanometers, whereas the thickness of the dielectric layersremains substantially constant, with the result that the aspect ratiosfor the features, i.e., their height divided by width, increases. Manytraditional deposition processes, such as physical vapor deposition(PVD) and chemical vapor deposition (CVD), have difficulty fillingstructures where the aspect ratio exceed 4:1, and particularly where itexceeds 10:1. Therefore, there is a great amount of ongoing effort beingdirected at the formation of void-free, nanometer-sized features havinghigh aspect ratios wherein the ratio of feature height to feature widthcan be 4:1 or higher. Additionally, as the feature widths decrease, thedevice current remains constant or increases, which results in anincreased current density in the feature.

Elemental aluminum (A1) and its alloys have been the traditional metalsused to form lines and plugs in semiconductor processing because ofaluminum's perceived low electrical resistivity, its superior adhesionto silicon dioxide (SiO₂), its ease of patterning, and the ability toobtain it in a highly pure form. However, aluminum has a higherelectrical resistivity than other more conductive metals such as copper,and aluminum also can suffer from electromigration leading to theformation of voids in the conductor.

Copper and its alloys have lower resistivities than aluminum andsignificantly higher electromigration resistance as compared toaluminum. These characteristics are important for supporting the highercurrent densities experienced at high levels of integration and increasedevice speed. Copper also has good thermal conductivity and is availablein a highly pure state. Therefore, copper is becoming a choice metal forfilling sub-quarter micron, high aspect ratio interconnect features onsemiconductor substrates.

Despite the desirability of using copper for semiconductor devicefabrication, choices of fabrication methods for depositing copper intovery high aspect ratio features, such as a 4:1, having 0.35 μ (or less)wide vias are limited. As a result of these process limitations,plating, which had previously been limited to the fabrication of lineson circuit boards, is just now being used to fill vias and contacts onsemiconductor devices.

Metal electroplating is generally known and can be achieved by a varietyof techniques. A typical method generally comprises physical vapordepositing a barrier layer over the feature surfaces, physical vapordepositing a conductive metal seed layer, preferably copper, over thebarrier layer, and then electroplating a conductive metal over the seedlayer to fill the structure/feature. Finally, the deposited layers andthe dielectric layers are planarized, such as by chemical mechanicalpolishing (CMP), to define a conductive interconnect feature.

FIG. 1 is a cross sectional view of a simplified typical fountain plater10 incorporating contact pins. Generally, the fountain plater 10includes an electrolyte container 12 having a top opening, a substrateholder 14 disposed above the electrolyte container 12, an anode 16disposed at a bottom portion of the electrolyte container 12 and acontact ring 20 contacting the substrate 22. A plurality of grooves 24are formed in the lower surface of the substrate holder 14. A vacuumpump (not shown) is coupled to the substrate holder 14 and communicateswith the grooves 24 to create a vacuum condition capable of securing thesubstrate 22 to the substrate holder 14 during processing. The contactring 20 comprises a plurality of metallic or semi-metallic contact pins26 distributed about the peripheral portion of the substrate 22 todefine a central substrate plating surface. The plurality of contactpins 26 extend radially inwardly over a narrow perimeter portion of thesubstrate 22 and contact a conductive seed layer of the substrate 22 atthe tips of the contact pins 26. A power supply (not shown) is attachedto the pins 26 thereby providing an electrical bias to the substrate 22.The substrate 22 is positioned above the cylindrical electrolytecontainer 12 and electrolyte flow impinges perpendicularly on thesubstrate plating surface during operation of the cell 10.

While present day electroplating cells, such as the one shown in FIG. 1,achieve acceptable results on larger scale substrates, a number ofobstacles impair consistent reliable electroplating onto substrateshaving micron-sized, high aspect ratio features. Generally, theseobstacles include providing uniform power distribution and currentdensity across the substrate plating surface to form a metal layerhaving uniform thickness, preventing unwanted edge and backsidedeposition to control contamination to the substrate being processed aswell as subsequent substrates, and maintaining a vacuum condition whichsecures the substrate to the substrate holder during processing. Also,the present day electroplating cells have not provided satisfactorythroughput to meet the demands of other processing systems and are notdesigned with a flexible architecture that is expandable to accommodatefuture designs rules and gap fill requirements. Moreover, the currentsystems have not addressed problems due to insufficient or discontinuousseed layers before the electroplating process. Furthermore, currentelectroplating system platforms have not provided post electrochemicaldeposition treatment, such as a rapid thermal anneal treatment, forenhancing deposition results within the same system platform.

One particular problem encountered in current electroplating processesis that the edge of the seed layer receives an excess amount ofdeposition, typically referred to as an edge bead, during theelectroplating process. The wafer has a seed layer deposited thereon andan electroplated layer electrochemically deposited over the seed layer.It has been observed that the edge of the seed layer receives a highercurrent density than the remainder of the seed layer, resulting in ahigher rate of deposition at the edge of the seed layer. The mechanicalstress at the edge of the seed layer is also higher than the remainderof the seed layer, causing the deposition at the edge of the seed layerto pull up and away from the edge of the wafer. The excess deposition istypically removed by a CMP process. However, during the CMP process, theexcess deposition 36 at the edge of the wafer typically tears off fromthe edge of the seed layer and may damage the adjacent portion of thewafer. The broken off metal may also damage the devices formed on thewafer. Thus, the number of properly formed devices is decreased and thecost per device formed is increased.

Additionally, current electroplating systems are incapable of performingnecessary processing steps without resorting to peripheral componentsand time intensive efforts. For example, analysis of the processingchemicals is required periodically during the plating process. Theanalysis determines the composition of the electrolyte to ensure properproportions of the ingredients. Conventional analysis is performed byextracting a sample of electrolyte from a test port and transferring thesample to a remote analyzer. The electrolyte composition is thenmanually adjusted according to the results of the analysis. The analysismust be performed frequently because the concentrations of the variouschemicals are in constant flux. However, the foregoing method is timeconsuming and limits the number of analyses which can be performed.

Therefore, there remains a need for an electrochemical deposition systemthat is designed with a flexible architecture that is expandable toaccommodate future designs rules and gap fill requirements and providessatisfactory throughput to meet the demands of other processing systems.Preferably, the apparatus removes the excess deposition at the edge ofthe wafer without damaging the devices formed on the wafer surface. Itwould be further desirable for the apparatus to be adaptable forperforming a wafer cleaning process after the excess deposition has beenremoved from the wafer, such as a spin-rinse-dry process. It would befurther desirable for the apparatus include a system that extends thereliability of depositions in features by enhancing an initialconductive layer for a subsequent electroplating process. It would alsobe desirable for the system to include one or more chemical analyzersintegrated with the processing system to provide real-time analysis ofthe electrolyte composition.

SUMMARY OF THE INVENTION

The present invention provides an electrochemical deposition system thatis designed with a flexible architecture that is expandable toaccommodate future designs and gap fill requirements and providessatisfactory throughput to meet the demands of other processing systems.The electro-chemical deposition system generally comprises a mainframehaving a mainframe wafer transfer robot, a loading station disposed inconnection with the mainframe, one or more processing cells disposed inconnection with the mainframe, and an electrolyte supply fluidlyconnected to the one or more electrical processing cells. Preferably,the electro-chemical deposition system includes an edge beadremoval/spin-rinse-dry (EBR/SRD) station disposed on the mainframeadjacent the loading station, a rapid thermal anneal chamber attached tothe loading station, a seed layer repair station disposed on themainframe, and a system controller for controlling the electrochemicaldeposition process and the components of the electrochemical depositionsystem.

One aspect of the invention provides an apparatus that removes theexcess deposition at the edge of the wafer without damaging the devicesformed on the wafer surface. The apparatus is adaptable for performing awafer cleaning process after the excess deposition has been removed fromthe wafer, such as a spin-rinse-dry process.

Another aspect of the invention provides an apparatus that extends thereliability of depositions in features by enhancing an initialconductive layer for a subsequent electroplating process.

Still another aspect of the invention provides an electrolytereplenishing system having a real-time chemical analyzer module and adosing module. The chemical analyzer module includes at least one andpreferably two analyzers operated by a controller and integrated with acontrol system of the electro-chemical deposition system. A sample lineprovides continuous flow of electrolyte from a main electrolyte tank tothe chemical analyzer module. A first analyzer determines theconcentrations of organic substances in the electrolyte while the secondanalyzer determines the concentrations of inorganic substances. Thedosing module is then activated to deliver the proper proportions ofchemicals to the main tank in response to the information obtained bythe chemical analyzer module. The real-time, on-line analyzer ispreferably disposed in a closed loop system with the electrolyte supply.The analyzer also includes one or more standards and one or morecalibration schemes to provide accurate measurements and prolong theuseful life of electrodes and sensors used in the analyzer.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features, advantages andobjects of the present invention are attained can be understood indetail, a more particular description of the invention, brieflysummarized above, may be had by reference to the embodiments thereofwhich are illustrated in the appended drawings.

It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a cross sectional view of a simplified typical fountain plater10 incorporating contact pins.

FIG. 2 is a perspective view of an electroplating system platform 200 ofthe invention.

FIG. 3 is a schematic view of an electroplating system platform 200 ofthe invention.

FIG. 4 is a schematic perspective view of a spin-rinse-dry (SRD) moduleof the present invention, incorporating rinsing and dissolving fluidinlets.

FIG. 5 is a side cross sectional view of the spin-rinse-dry (SRD) moduleof FIG. 4 and shows a substrate in a processing position verticallydisposed between fluid inlets.

FIG. 6 is a cross sectional view of an electroplating process cell 400according to the invention.

FIG. 7 is a schematic diagram of an electrolyte replenishing system 220.

FIG. 8 is a cross sectional view of a rapid thermal anneal chamber.

FIG. 9 is a perspective view of a cathode contact ring.

FIG. 10 is a partial cross sectional view of a wafer holder assembly.

FIG. 11 is a cross sectional view of an encapsulated anode.

FIG. 12 is a process head assembly having a rotatable head assembly2410.

FIGS. 13a and 13 b are cross sectional views of embodiments of adegasser module.

FIG. 14 is a cross sectional view of a combined edge beadremoval/spin-rinse-dry (EBRISRD) module showing a substrate in aprocessing position vertically disposed between fluid inlets.

FIG. 15 is a top schematic view of an EBR/SRD module illustrating oneembodiment of the nozzle positions for edge bead removal.

FIG. 16 is a side view of a nozzle 2150 disposed in relation to a wafer2122 being processed.

FIG. 17 is a cross section view of an electroless deposition processing(EDP) cell.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 is a perspective view of an electroplating system platform 200 ofthe invention. FIG. 3 is a schematic view of an electroplating systemplatform 200 of the invention. Referring to both FIGS. 2 and 3, theelectroplating system platform 200 generally comprises a loading station210, a thermal anneal chamber 211, a mainframe 214, and an electrolytereplenishing system 220. The mainframe 214 generally comprises amainframe transfer station 216, a spin-rinse dry (SRD) station 212, aplurality of processing stations 218, and a seed layer repair station215. Preferably, the electroplating system platform 200, particularlythe mainframe 214, is enclosed in a clean environment using panels suchas plexiglass panels. The mainframe 214 includes a base 217 havingcut-outs to support various stations needed to complete theelectro-chemical deposition process. The base 217 is preferably made ofaluminum, stainless steel or other rigid materials that can support thevarious stations disposed thereon. A chemical protection coating, suchas Halar™, ethylene-chloro-tri-fluoro-ethaylene (ECTFE), or otherprotective coatings, is preferably disposed over the surfaces of thebase 217 that are exposed to potential chemical corrosion. Preferably,the protective coating provides good conformal coverage over the metalbase 217, adheres well to the metal base 217, provides good ductility,and resists cracking under normal operating conditions of the system.Each processing station 218 includes one or more processing cells 240.An electrolyte replenishing system 220 is positioned adjacent themainframe 214 and connected to the process cells 240 individually tocirculate electrolyte used for the electroplating process. Theelectroplating system platform 200 also includes a power supply station221 for providing electrical power to the system and a control system222, typically comprising a programmable microprocessor.

The loading station 210 preferably includes one or more wafer cassettereceiving areas 224, one or more loading station transfer robots 228 andat least one wafer orientor 230. The number of wafer cassette receivingareas, loading station transfer robots 228 and wafer orientor includedin the loading station 210 can be configured according to the desiredthroughput of the system. As shown for one embodiment in FIGS. 2 and 3,the loading station 210 includes two wafer cassette receiving areas 224,two loading station transfer robots 228 and one wafer orientor 230. Awafer cassette 232 containing wafers 234 is loaded onto the wafercassette receiving area 224 to introduce wafers 234 into theelectroplating system platform. The loading station transfer robot 228transfers wafers 234 between the wafer cassette 232 and the waferorientor 230. The loading station transfer robot 228 comprises a typicaltransfer robot commonly known in the art. The wafer orientor 230positions each wafer 234 in a desired orientation to ensure that thewafer is properly processed. The loading station transfer robot 228 alsotransfers wafers 234 between the loading station 210 and the SRD station212 and between the loading station 210 and the thermal anneal chamber211. The loading station 210 preferably also includes a wafer cassette231 for temporary storage of wafers as needed to facilitate efficienttransfer of wafers through the system.

FIG. 4 is a schematic perspective view of a spin-rinse-dry (SRD) moduleof the present invention, incorporating rinsing and dissolving fluidinlets. FIG. 5 is a side cross sectional view of the spin-rinse-dry(SRD) module of FIG. 4 and shows a substrate in a processing positionvertically disposed between fluid inlets. Preferably, the SRD station212 includes one or more SRD modules 236 and one or more waferpass-through cassettes 238. Preferably, the SRD station 212 includes twoSRD modules 236 corresponding to the number of loading station transferrobots 228, and a wafer pass-through cassette 238 is positioned aboveeach SRD module 236. The wafer pass-through cassette 238 facilitateswafer transfer between the loading station 210 and the mainframe 214.The wafer pass-through cassette 238 provides access to and from both theloading station transfer robot 228 and a robot in the mainframe transferstation 216.

Referring to FIGS. 4 and 5, the SRD module 236 comprises a bottom 330 aand a sidewall 330 b, and an upper shield 330 c which collectivelydefine a SRD module bowl 330 d, where the shield attaches to thesidewall and assists in retaining the fluids within the SRD module.Alternatively, a removable cover could also be used. A pedestal 336,located in the SRD module, includes a pedestal support 332 and apedestal actuator 334. The pedestal 336 supports the substrate 338(shown in FIG. 5) on the pedestal upper surface during processing. Thepedestal actuator 334 rotates the pedestal to spin the substrate andraises and lowers the pedestal as described below. The substrate may beheld in place on the pedestal by a plurality of clamps 337. The clampspivot with centrifugal force and engage the substrate preferably in theedge exclusion zone of the substrate. In a preferred embodiment, theclamps engage the substrate only when the substrate lifts off thepedestal during the processing. Vacuum passages (not shown) may also beused as well as other holding elements. The pedestal has a plurality ofpedestal arms 336 a and 336 b, so that the fluid through the secondnozzle may impact as much surface area on the lower surface of thesubstrate as is practical. An outlet 339 allows fluid to be removed fromthe SRD module. The terms “below”, “above”, “bottom”, “top”, “up”,“down”, “upper”, and “lower” and other positional terms used herein areshown with respect to the embodiments in the figures and may be varieddepending on the relative orientation of the processing apparatus.

A first conduit 346, through which a first fluid 347 flows, is connectedto a valve 347 a. The conduit may be hose, pipe, tube, or other fluidcontaining conduits. The valve 347 a controls the flow of the firstfluid 347 and may be selected from a variety of valves including aneedle, globe, butterfly, or other valve types and may include a valveactuator, such as a solenoid, that can be controlled with a controller362. The conduit 346 connects to a first fluid inlet 340 that is locatedabove the substrate and includes a mounting portion 342 to attach to theSRD module and a connecting portion 344 to attach to the conduit 346.The first fluid inlet is shown with a single first nozzle 348 to delivera first fluid 347 under pressure onto the substrate upper surface.However, multiple nozzles could be used and multiple fluid inlets couldbe positioned about the inner perimeter of the SRD module. Preferably,nozzles placed above the substrate should be outside the diameter of thesubstrate to lessen the risk of the nozzles dripping on the substrate.The first fluid inlet could be mounted in a variety of locations,including through a cover positioned above the substrate. Additionally,the nozzle may articulate to a variety of positions using anarticulating member 343, such as a ball and socket joint.

Similar to the first conduit and related elements described above, asecond conduit 352 is connected to a control valve 349 a and a secondfluid inlet 350 with a second nozzle 351. The second fluid inlet 350 isshown below the substrate and angled upward to direct a second fluidunder the substrate through the second nozzle 351. Similar to the firstfluid inlet, the second fluid inlet may include a plurality of nozzles,a plurality of fluid inlets and mounting locations, and a plurality oforientations including using the articulating member 353. Each fluidinlet could be extended into the SRD module at a variety of positions.For instance, if the flow is desired to be a certain angle that isdirected back toward the SRD module periphery along the edge of thesubstrate, the nozzles could be extended radially inward and thedischarge from the nozzles be directed back toward the SRI moduleperiphery.

The controller 362 could individually control the two fluids and theirrespective flow rates, pressure, and timing, and any associated valving,as well as the spin cycle(s). The controller could be remotely located,for instance, in a control panel or control room and the plumbingcontrolled with remote actuators. An alternative embodiment, shown indashed lines, provides an auxiliary fluid inlet 346 a connected to thefirst conduit 346 with a conduit 346 b and having a control valve 346 c,which may be used to flow a rinsing fluid on the backside of thesubstrate after the dissolving fluid is flown without having to reorientthe substrate or switch the flow through the second fluid inlet to arinsing fluid.

In one embodiment, the substrate is mounted with the deposition surfaceof the disposed face up in the SRD module bowl. As will be explainedbelow, for such an arrangement, the first fluid inlet would generallyflow a rinsing fluid, typically deionized water or alcohol.Consequently, the backside of the substrate would be mounted facing downand a fluid flowing through the second fluid inlet would be a dissolvingfluid, such as an acid, including hydrochloric acid, sulfuric acid,phosphoric acid, hydrofluoric acid, or other dissolving liquids orfluids, depending on the material to be dissolved. Alternatively, thefirst fluid and the second fluid are both rinsing fluids, such asdeionized water or alcohol, when the desired process is to rinse theprocessed substrate.

In operation, the pedestal is in a raised position, shown in FIG. 4, anda robot (not shown) places the substrate, front side up, onto thepedestal. The pedestal lowers the substrate to a processing positionwhere the substrate is vertically disposed between the first and thesecond fluid inlets. Generally, the pedestal actuator rotates thepedestal between about 5 to about 5000 rpm, with a typical range betweenabout 20 to about 2000 rpm for a 200 mm substrate. The rotation causesthe lower end 337 a of the clamps to rotate outward about pivot 337 b,toward the periphery of the SRD module sidewall, due to centrifugalforce. The clamp rotation forces the upper end 337 c of the clamp inwardand downward to center and hold the substrate 338 in position on thepedestal 336, preferably along the substrate edge. The clamps may rotateinto position without touching the substrate and hold the substrate inposition on the pedestal only if the substrate significantly lifts offthe pedestal during processing. With the pedestal rotating thesubstrate, a rinsing fluid is delivered onto the substrate front sidethrough the first fluid inlet 340. The second fluid, such as an acid, isdelivered to the backside surface through the second fluid inlet toremove any unwanted deposits. The dissolving fluid chemically reactswith the deposited material and dissolves and then flushes the materialaway from the substrate backside and other areas where any unwanteddeposits are located. In a preferred embodiment, the rinsing fluid isadjusted to flow at a greater rate than the dissolving fluid to helpprotect the front side of the substrate from the dissolving fluid. Thefirst and second fluid inlets are located for optimal performancedepending on the size of the substrate, the respective flow rates, spraypatterns, and amount and type of deposits to be removed, among otherfactors. In some instances, the rinsing fluid could be routed to thesecond fluid inlet after a dissolving fluid has dissolved the unwanteddeposits to rinse the backside of the substrate. In other instances, anauxiliary fluid inlet connected to flow rinsing fluid on the backside ofthe substrate could be used to rinse any dissolving fluid residue fromthe backside. After rinsing the front side and/or backside of thesubstrate, the fluid(s) flow is stopped and the pedestal continues torotate, spinning the substrate, and thereby effectively drying thesurface.

The fluid(s) is generally delivered in a spray pattern, which may bevaried depending on the particular nozzle spray pattern desired and mayinclude a fan, jet, conical, and other patterns. One spray pattern forthe first and second fluids through the respective fluid inlets, whenthe first fluid is a rinsing fluid, is fan pattern with a pressure ofabout 10 to about 15 pounds per square inch (psi) and a flow rate ofabout 1 to about 3 gallons per minute (gpm) for a 200 mm wafer.

The invention could also be used to remove the unwanted deposits alongthe edge of the substrate to create an edge exclusion zone. Byadjustment of the orientation and placement of the nozzles, the flowrates of the fluids, the rotational speed of the substrate, and thechemical composition of the fluids, the unwanted deposits could beremoved from the edge and/or edge exclusion zone of the substrate aswell. Thus, substantially preventing dissolution of the depositedmaterial on the front side surface may not necessarily include the edgeor edge exclusion zone of the substrate. Also, preventing dissolution ofthe deposited material on the front side surface is intended to includeat least preventing the dissolution so that the front side with thedeposited material is not impaired beyond a commercial value.

One method of accomplishing the edge exclusion zone dissolution processis to rotate the disk at a slower speed, such as about 100 to about 1000rpm, while dispensing the dissolving fluid on the backside of thesubstrate. The centrifugal force moves the dissolving fluid to the edgeof the substrate and forms a layer of fluid around the edge due tosurface tension of the fluid, so that the dissolving fluid overlaps fromthe backside to the front side in the edge area of the substrate. Therotational speed of the substrate and the flow rate of the dissolvingfluid may be used to determine the extent of the overlap onto the frontside. For instance, a decrease in rotational speed or an increase inflow results in a less overlap of fluid to the opposing side, e.g., thefront side. Additionally, the flow rate and flow angle of the rinsingfluid delivered to the front side can be adjusted to offset the layer ofdissolving fluid onto the edge and/or frontside of the substrate. Insome instances, the dissolving fluid may be used initially without therinsing fluid to obtain the edge and/or edge exclusion zone removal,followed by the rinsing/dissolving process of the present inventiondescribed above.

FIG. 14 is a cross sectional view of a combined edge beadremoval/spin-rinse-dry (EBR/SRD) module showing a substrate in aprocessing position vertically disposed between fluid inlets. Thisembodiment of the invention is useful for both edge bead removal (EBR)and spin-rinse-dry (SRD) processes. The EBR/SRD module is preferablydisposed in the SRD station 212 (see FIG. 3). The EBR/SRD module 2200comprises a container 2102, a wafer holder assembly 2104 and afluid/chemical delivery assembly 2106. The container 2102 preferablyincludes a cylindrical sidewall 2108, a container bottom 2110 having acentral opening 2112, and an upturned inner wall 2114 extending upwardlyfrom the peripheral edge of the central opening 2112. A fluid outlet2116 is connected to the container bottom 2110 to facilitate draining ofthe used fluids and chemicals from the EBR/SRD module 2200.

The wafer holder assembly 2104 is disposed above the central opening2112 and includes a lift assembly 2118 and a rotation assembly 2120 thatextends through the central opening 2112. The lift assembly 2118preferably comprises a bellows-type lift or a lead-screw stepper motortype lift assembly, which are well known in the art and commerciallyavailable. The lift assembly 2118 facilitates transfer and positioningof the wafer 2122 on the wafer holder assembly 2104 between variousvertical positions. The rotation assembly 2120 preferably comprises arotary motor that is attached below the lift assembly. The rotationassembly 2120 rotates the wafer 2122 during the edge bead removalprocess.

The wafer holder assembly 2104 preferably comprises a vacuum chuck 2124that secures a wafer 2122 from the wafer backside and does not obstructthe wafer edge 2126. Preferably, an annular seal 2128, such as acompressible O-ring, is disposed at a peripheral portion of the vacuumchuck surface to seal the vacuum chuck 2124 from the fluids andchemicals used during the edge bead removal process. The wafer holderassembly 2104 preferably includes a wafer lift 2130 that facilitatestransfer of a wafer from a robot blade of a transfer robot onto thewafer holder assembly 2104. The wafer lift 2130, as shown in FIG. 14,comprises a spider clip assembly that also can be used to secure a waferduring a spin-rinse-dry process. The spider clip assembly comprises aplurality of arms 2134 extending from an annular base 2136 and a spiderclip 2138 pivotally disposed at the distal end of the arm 2134. Theannular base 2136 includes a downwardly extending wall 2137 thatoverlaps the upturned inner wall 2114 to contain fluids used duringprocessing inside the container 2102. The spider clip 2138 includes anupper surface 2140 for receiving the wafer, a clamp portion 2142 forclamping the wafer, and a lower portion 2144 that causes the clampportion 2142 to engage the edge of the wafer due to centrifugal forcewhen the wafer holder assembly is rotated. Alternatively, the wafer lift2130 comprises commonly used wafer lifts in various wafer processingapparatus, such as a set of lift pins or a lift hoop disposed on a liftplatform or lift ring in or around the vacuum chuck body.

The fluid/chemical delivery assembly 2106 comprises one or more nozzles2150 disposed on one or more dispense arms 2152. The dispense arm 2152extends through the container sidewall 2108 and is attached to anactuator 2154 that extends and retracts to vary the position of thenozzle 2150 over the substrate 2122. By having an extendable dispensearm 2152, the nozzle can be positioned over the wafer to point thenozzle from an interior portion of the wafer toward the edge of thewafer, which enhances the control over the delivery of theetchant/fluids to the wafer edge. Alternatively, the dispense arm 2152is fixedly attached to the container sidewall 2108, and the nozzle 2150is secured to the dispense arm in a position that does not interferewith vertical wafer movement in the container 2102.

Preferably, the dispense arm 2152 includes one or more conduitsextending through the dispense arm for connecting the nozzle 2150 to anetchant source. A variety of etchants are well known in the art forremoving deposited metal from a substrate, such as nitric acid and otheracids available commercially. Alternatively, the nozzle 2150 isconnected through a flexible tubing disposed through the conduit in thedispense arm 2152. The nozzles 2150 can be selectively connected to oneor more chemical/fluid sources, such as a deionized water source 2160and an etchant source 2162, and a computer control 2164 switches theconnection between the one or more fluid/chemical sources according to adesired program. Alternatively, a first set of nozzles are connected tothe deionized water source and a second set of nozzles are connected tothe etchant source, and the nozzles are selectively activated to providefluids to the wafer.

Preferably, an additional set of lower nozzles 2170 are disposed at aposition below the wafer, preferably vertically aligned correspondinglyto the positions of nozzles 2150. The lower nozzles 2170 are selectivelyconnected to a deionized water source 2160 and an etchant source 2162,and the fluid delivered by the nozzles 2170 is controlled by thecontroller 2164. Preferably, the nozzles 2170 are directed to deliverfluids to a peripheral portion of the backside of the wafer. The lowernozzles 2170 are preferably disposed at positions that do not interferewith the movement of the wafer lift 2130. The lower nozzle 2170 can alsobe attached to an actuator 2174 through an arm 2176 that retracts andextends to position the nozzles 2170 at desired locations.Alternatively, the wafer lift 2130 is not rotated during processing toprevent interference with the lower nozzles 2170. The EBR/SRD module2200 preferably also include a dedicated deionized water nozzle 2172disposed to deliver deionized water to a central portion of the uppersurface of the wafer.

Preferably, the nozzles 2150 are disposed at an angled to provide fluidsnear a peripheral portion of the wafer at a substantially tangentialdirection. FIG. 15 is a top schematic view of an EBR/SRD moduleillustrating one embodiment of the nozzle positions for edge beadremoval. As shown, three nozzles 2150 are disposed substantially evenlyspaced about an interior surface of the container sidewall 2108. Eachnozzle 2150 is disposed to provide fluids to an edge portion of thewafer and is positioned to provide sufficient space to allow verticalwafer movement between a processing position and a transfer position.Preferably, the fluid delivery or spray pattern is controlled by theshape of the nozzle and the fluid pressure to limit fluid delivery to aselected edge exclusion range. For example, the etchant is restricted toan outer 3 mm annular portion of the wafer to achieve 3 mm edgeexclusion. The nozzles are positioned to provide the etchant at an angleof incidence to the surface of the wafer that controls splashing of theetchant as the etchant comes into contact with the wafer. FIG. 16 is aside view of a nozzle 2150 disposed in relation to a wafer 2122 beingprocessed. Preferably, the angle of incidence, α, of the etchant to thewafer is between about 0 degrees and about 45 degrees, more preferablybetween about 10 degrees and about 30 degrees.

The wafer 2122 is rotated during the edge bead removal process toprovide substantially equal exposure to the etchant at the peripheralportion of the wafer. Preferably, the wafer 2122 is rotated in the samedirection as the direction of the etchant spray pattern to facilitatecontrolled edge bead removal. For example, as shown in FIG. 15, thewafer is rotated in a counter-clockwise direction (arrow A) whichcorresponds to the counter-clockwise spray pattern. The wafer ispreferably rotated between about 100 rpm to about 1000 rpm, morepreferably between about 500 rpm and about 700 rpm. The effective etchrate (ie., the amount of copper removed divided by the time required forremoval) is a function of the etch rate of the etchant, the velocity ofthe etchant contacting the wafer edge, the temperature of the etchant,and the velocity of the wafer rotation. These parameters can be variedto achieve particular desired results.

In operation, a wafer 2122 is positioned above the wafer holder assembly2104 of the EBR/SRD module 2200, and the wafer lift 2130 lifts the waferoff of a transfer robot blade. The robot blade retracts and the waferlift 2130 lowers the wafer onto the vacuum chuck 2124. The vacuum systemis activated to secure the wafer 2122 thereon, and the wafer holderassembly 2104 with the wafer disposed thereon is rotated as the nozzles2150 deliver the etchant onto the peripheral portion of the wafer 2122.Preferably, the lower nozzles 2170 also deliver etchant to the backsideof the wafer during the edge bead removal process. Preferably, thedeionized water nozzle 2172 delivers deionized water to the centralportion of the wafer during the edge bead removal process to preventunintended etching by the etchant that has splashed onto a centralportion of the wafer surface. The etching process is performed for apre-determined time period sufficient to remove the excess deposition onthe wafer edge (ie., edge bead). The wafer is preferably cleanedutilizing deionized water in a spin-rinse-dry process. Thespin-rinse-dry process typically involves delivering deionized water tothe wafer to rinse residual etchant from the wafer and spining the waferat a high speed to dry the wafer. For a spin-rinse-dry process,preferably all of the nozzles 2150, 2170 and 2172 delivers deionizedwater to rinse the wafer as the wafer rotates. After the wafer has beenrinsed, the wafer is spun dry and transferred out of the EBRISRD module2200 for further processing.

The EBR/SRD module 220 or the SRD module 238 is disposed adjacent theloading station 210 and serves as the connection between the loadingstation 210 and the mainframe 214. Referring back to FIGS. 2 and 3, themainframe 214, as shown, includes two processing stations 218 disposedon opposite sides, each processing station 218 having two processingcells 240. The mainframe transfer station 216 includes a mainframetransfer robot 242 disposed centrally to provide substrate transferbetween various stations on the mainframe. Preferably, the mainframetransfer robot 242 comprises a plurality of individual robot arms 2402that provides independent access of wafers in the processing stations218 the SRD stations 212, the seed layer repair stations, and otherprocessing stations disposed on or in connection with the mainframe. Asshown in FIG. 3, the mainframe transfer robot 242 comprises two robotarms 2402, corresponding to the number of processing cells 240 perprocessing station 218. Each robot arm 2402 includes an end effector2404 for holding a wafer during a wafer transfer. Preferably, each robotarm 2402 is operable independently of the other arm to facilitateindependent transfers of wafers in the system. Alternatively, the robotarms 2402 operate in a linked fashion such that one robot extends as theother robot arm retracts.

FIG. 3 is a top schematic view of a mainframe transfer robot having aflipper robot incorporated therein. The mainframe transfer robot 242 asshown in FIG. 3 serves to transfer wafers between different stationsattached the mainframe station, including the processing stations andthe SRD stations. The mainframe transfer robot 242 includes a pluralityof robot arms 2402 (two shown), and a flipper robot 2404 is attached asan end effector for each of the robot arms 2402. Flipper robots aregenerally known in the art and can be attached as end effectors forwafer handling robots, such as model RR701, available from RorzeAutomation, Inc., located in Milpitas, Calif. The main transfer robot242 having a flipper robot as the end effector is capable oftransferring substrates between different stations attached to themainframe as well as flipping the substrate being transferred to thedesired surface orientation For example, the flipper robot flips thesubstrate processing surface face-down for the electroplating process inthe processing cell 240 and flips the substrate processing surfaceface-up for other processes, such as the spin-rinse-dry process.Preferably, the mainframe transfer robot 242 provides independent robotmotion along the X-Y-Z axes by the robot arm 2402 and independentsubstrate flipping rotation by the flipper robot end effector 2404.

Preferably, one or more electroless deposition cells or modules aredisposed in the seed layer repair station 215. The electrolessdeposition cells, herein referred to as an electroless depositionprocessing (EDP) cell, perform an electroless deposition process. TheEDP cell can be located at the rearward portions, distal from the entryof the substrates, of the electroplating system platform 200. In theembodiment shown, two EDP cells can be arranged side-by-side for greaterthroughput rates.

FIG. 17 is a schematic cross sectional view of one EDP cell 3010. TheEDP cell 3010 includes a bottom 3012, a sidewall 3014, and an angularlydisposed upper shield 3016 attached to the sidewall 3014 and open in themiddle of the shield. Alternatively, a removable cover (not shown) couldbe used. A pedestal 3018 is generally disposed in a central location ofthe cell 3010 and includes a pedestal actuator 3020. The pedestalactuator 3020 rotates the pedestal 3018 to spin a substrate 3022 mountedthereon between about 10 to about 2000 RPMs. The pedestal can be heatedso that the substrate temperature is between about 15° C. to about 100°C., and preferably about 60° C. A pedestal lift 3024 raises and lowersthe pedestal 3018. The substrate 3022 can be held in position by avacuum chuck 3026 mounted to the top of the pedestal 3018. In addition,the pedestal 3018 can lower the substrate 3022 to a vertical positionaligned with a plurality of clamps 3028. The clamps 3028 pivot withcentrifugal force and engage the substrate 3022 preferably on an edge ofthe substrate. The pedestal 3018 also includes a downwardly disposedannular shield 3030 of greater diameter than a corresponding upwardlydisposed annular shield 3032 coupled to the bottom of the cell 3010. Theinteraction of the two annular shields 3030, 3032 protects the pedestal3018 and associated components from the fluids in the cell 3010. Atleast one fluid outlet 3034 is disposed in the bottom of the 3010 cellto allow fluids to exit the cell.

A first conduit 3036, through which an electroless deposition fluidflows, is coupled to the cell 3010. The conduit 3036 can be a hose,pipe, tube, or other fluid containing conduit. An electroless depositionfluid valve 3038 controls the flow of the electroless deposition fluid,where the valves disclosed herein can be a needle, globe, butterfly, orother type of valve and can include a valve actuator, such as asolenoid. An electroless deposition fluid container 3044 is connected tothe valve 3038 that can be controlled with a controller 3040. A seriesof valves 3042 a-f are connected to various chemical sources (notshown), where the valves 3042 a-f can be separately controlled with thecontroller 3040. Preferably, the electroless deposition fluid is mixedon an as-needed basis in individual application quantities fordeposition on the substrate 3022 and not significantly before thedeposition to avoid premature electroless deposition in the conduit 3036and associated elements. The valves 3038, 3042 a-f are thereforepreferably located in close proximity to the cell 3010. The firstconduit 3036 connects to an first fluid inlet 3046 disposed above thesubstrate 3022 when the substrate is disposed in a lowered position andpreferably is coupled to an articulating member 3048, such as a ball andsocket joint, to allow movement of the inlet 3046 and to allowadjustment of the angle of the inlet 3046 in the cell 3010. A firstnozzle 3050 is connected to the end of the inlet 3046 and is directedtoward the pedestal 3018. The fluid(s) is generally delivered in a spraypattern, which may be varied depending on the particular nozzle spraypattern desired and may include a fan, jet, conical, and other patterns.Preferably, the nozzle 3050 is located outside the periphery of thesubstrate 3022 to allow the substrate to be raised and lowered withoutinterference. Alternatively, the nozzle 3050 can be articulated towardthe periphery of the cell 3010 with an actuator (not shown) that movesthe nozzle 3050 laterally, vertically or some combination thereof toprovide vertical clearance for the substrate 3022 as the substrate israised or lowered.

Similar to the first conduit and related elements, a second conduit 3052is disposed through the sidewall 3014. The second conduit 3052 providesa path for rinsing fluid, such as deionized water or alcohol, that isused to rinse the substrate 3022 after the electroless deposition. Asecond inlet 3054 is connected to the second conduit 3052 and a secondnozzle 3056 is connected to the second inlet 3054. An articulatingmember 3059 is coupled to the second inlet 3054 and can be used to allowmovement and adjustment of the angle of the inlet relative to the cell3010. A second valve 3058 is connected to the second conduit 3052 andpreferably controls the rinsing fluid timing and flow. The secondconduit can also be coupled to a source of low concentration of acid orother fluids and a valve for controlling the fluid. Alternatively, theacid supply can be coupled to a separate conduit (not shown). Exemplaryfluids include hydrochloric acid, sulfuric acid, phosphoric acid,hydrofluoric acid, or other liquids or fluids that can be used to coatthe substrate surface after the electroless deposition to protect thelayer from oxidation and other contaminants prior to the electroplatingprocess. The substrate can thus be transferred for subsequent processingsuch as electroplating in a “wet” state to minimize oxidation and othercontaminants. The ability to transfer in a wet state is further enhancedif the substrate is maintained in a face up position for a period oftime subsequent to the electroless deposition process.

The controller 3040 preferably controls each valve and therefore eachfluid timing and flow. The controller 3040 preferably also controls thesubstrate spin and raising and lowering of the pedestal and hence thesubstrate disposed thereon. The controller 3040 could be remotelylocated, for instance, in a control panel (not shown) or control roomand the plumbing controlled with remote actuators.

In operation, a robot (not shown) delivers the substrate 3022 face up tothe EDP cell 3010. The substrate 3022 already has a seed layer depositedthereon such as by PVD or IMP processing. The pedestal raises 3018 andthe vacuum chuck 3026 engages the underside of the substrate 3022. Therobot retracts and the pedestal 3018 lowers to a processing elevation.The controller 3040 actuates the valves 3042 a-f to provide chemicalsinto the electroless fluid container 3044, the chemicals are mixed, andthe controller actuates the electroless deposition fluid valve 3038 toopen and allow a certain quantity of electroless deposition fluid intothe first inlet 3046 and through the first nozzle 3050. Preferably, thepedestal 3018 spins at a relatively slow speed of about 10 to about 500RPMs, allowing a quantity of fluid to uniformly coat the substrate 3022.The spin direction can be reversed in an alternating fashion to assistin spreading the fluid evenly across the substrate. The electrolessdeposition fluid valve 3038 is closed. The electroless deposition fluidauto-catalytically forms a layer over the pre-deposited seed layer andjoins vacancies in the prior deposited layer to provide a more completecoating even in high aspect ratio features. Preferably, the electrolessdeposition process deposits from about 100 Å to about 400 Å for mostsubstrates.

The second valve 3058 opens and a rinsing fluid flows through the secondconduit 3052 and is sprayed onto the substrate 3022 through the secondnozzle 3056. Preferably, the pedestal 3018 rotates at a faster speed ofabout 100 to about 500 RPMs as the remaining electroless depositionfluid is rinsed from the substrate 3022 and is drained through theoutlet 3034 and discarded. The substrate can be coated with an acid orother coating fluid. In some instances, the pedestal 3018 can spin at ahigher speed of about 500 to about 2000 RPMs to spin dry the substrate3022.

The pedestal 3018 stops rotating and raises the substrate 3022 to aposition above the EDP cell 3010. The vacuum chuck 3026 releases thesubstrate 3022 and the robot retrieves the substrate for furtherprocessing in the electroplating cell.

FIG. 6 is a cross sectional view of an electroplating process cell 400according to the invention. The electroplating process cell 400 as shownin FIG. 6 is the same as the electroplating process cell 240 as shown inFIGS. 2 and 3. The processing cell 400 generally comprises a headassembly 410, a process kit 420 and an electrolyte collector 440.Preferably, the electrolyte collector 440 is secured onto the body 442of the mainframe 214 over an opening 443 that defines the location forplacement of the process kit 420. The electrolyte collector 440 includesan inner wall 446, an outer wall 448 and a bottom 447 connecting thewalls. An electrolyte outlet 449 is disposed through the bottom 447 ofthe electrolyte collector 440 and connected to the electrolytereplenishing system 220 (shown in FIG. 2) through tubes, hoses, pipes orother fluid transfer connectors.

The head assembly 410 is mounted onto a head assembly frame 452. Thehead assembly frame 452 includes a mounting post 454 and a cantileverarm 456. The mounting post 454 is mounted onto the body 442 of themainframe 214, and the cantilever arm 456 extends laterally from anupper portion of the mounting post 454. Preferably, the mounting post454 provides rotational movement with respect to a vertical axis alongthe mounting post to allow rotation of the head assembly 410. The headassembly 410 is attached to a mounting plate 460 disposed at the distalend of the cantilever arm 456. The lower end of the cantilever arm 456is connected to a cantilever arm actuator 457, such as a pneumaticcylinder, mounted on the mounting post 454. The cantilever arm actuator457 provides pivotal movement of the cantilever arm 456 with respect tothe joint between the cantilever arm 456 and the mounting post 454. Whenthe cantilever arm actuator 457 is retracted, the cantilever arm 456moves the head assembly 410 away from the process kit 420 to provide thespacing required to remove and/or replace the process kit 420 from theelectroplating process cell 400. When the cantilever arm actuator 457 isextended, the cantilever arm 456 moves the head assembly 410 toward theprocess kit 420 to position the wafer in the head assembly 410 in aprocessing position.

The head assembly 410 generally comprises a wafer holder assembly 450and a wafer assembly actuator 458. The wafer assembly actuator 458 ismounted onto the mounting plate 460, and includes a head assembly shaft462 extending downwardly through the mounting plate 460. The lower endof the head assembly shaft 462 is connected to the wafer holder assembly450 to position the wafer holder assembly 450 in a processing positionand in a wafer loading position.

The wafer holder assembly 450 generally comprises a wafer holder 464 anda cathode contact ring 466. FIG. 9 is a perspective view of a cathodecontact ring. The cathode contact ring 1800 as shown in FIG. 9 comprisesa conductive metal or a metal alloy, such as stainless steel, copper,silver, gold, platinum, titanium, tantalum, and other conductivematerials, or a combination of conductive materials, such as stainlesssteel coated with platinum. The cathode contact ring 1800 includes anupper mounting portion 1810 adapted for mounting the cathode contactring onto the wafer holder assembly and a lower substrate receivingportion 1820 adapted for receiving a substrate therein. The substratereceiving portion 1820 includes an annular substrate seating surface1822 having a plurality of contact pads or bumps 1824 disposed thereonand preferably evenly spaced apart. When a substrate is positioned onthe substrate seating surface 1822, the contact pads 1824 physicallycontact a peripheral region of the substrate to provide electricalcontact to the electroplating seed layer on the substrate depositionsurface. Preferably, the contact pads 1824 are coated with a noblemetal, such as platinum or gold, that is resistant to oxidation.

The exposed surfaces of the cathode contact ring, except the surfaces ofthe contact pads that come in contact with the substrate, are preferablytreated to provide hydrophilic surfaces or coated with a material thatexhibits hydrophilic properties. Hydrophilic materials and hydrophilicsurface treatments are known in the art. One company providing ahydrophilic surface treatment is Millipore Corporation, located inBedford, Mass. The hydrophilic surface significantly reduces beading ofthe electrolyte on the surfaces of the cathode contact ring and promotessmooth dripping of the electrolyte from the cathode contact ring afterthe cathode contact ring is removed from the electroplating bath orelectrolyte. By providing hydrophilic surfaces on the cathode contactring that facilitate run-off of the electrolyte, plating defects causedby residual electrolyte on the cathode contact ring are significantlyreduced. The inventors also contemplate application of this hydrophilictreatment or coating in other embodiments of cathode contact rings toreduce residual electrolyte beading on the cathode contact ring and theplating defects on a subsequently processed substrate that may resulttherefrom. Other contact ring designs are useful in the electroplatingprocessing cell according to the invention, such as the contact ringdesigns described in commonly assigned and copending U.S. PatentApplication Ser. No. 09/201,486 entitled “Cathode Contact Ring ForElectrochemical Deposition”, filed on Nov. 30, 1998, which is herebyincorporated by reference in its entirety.

FIG. 10 is a partial cross sectional view of a wafer holder assembly.The wafer holder 464 is preferably positioned above the cathode contactring 466 and comprises a bladder assembly 470 that provides pressure tothe backside of a wafer and ensures electrical contact between the waferplating surface and the cathode contact ring 466. The inflatable bladderassembly 470 is disposed on a wafer holder plate 832. The bladderassembly 470 includes an inflatable bladder 836 attached to the backsurface of an intermediary wafer holder plate 1910. A fluid source 838supplies a fluid, i.e., a gas or liquid, to the bladder 836 allowing thebladder 836 to be inflated to varying degrees. Preferably, a portion ofthe inflatable bladder 836 is sealingly attached to the back surface1912 of the intermediary wafer holder plate 1910 using an adhesive orother bonding material. The front surface 1914 of the intermediary waferholder plate 1910 is adapted to receive a wafer or substrate 821 to beprocessed, and an elastomeric O-ring 1916 is disposed in an annulargroove 1918 on the front surface 1914 of the intermediary wafer holderplate 1910 to contact a peripheral portion of the wafer back surface.The elastomeric o-ring 1916 provides a seal between the wafer backsurface and the front surface of the intermediary wafer holder plate.Preferably, the intermediary wafer holder plate includes a plurality ofbores or holes 1920 extending through the plate that are in fluidcommunication with the vacuum port (not shown) to facilitate securingthe wafer on the wafer holder using a vacuum force applied to thebackside of the wafer. The inflatable bladder does not directly contacta wafer being processed, and thus, the risk of cutting or damaging theinflatable bladder during wafer transfers is significantly reduced. Theelastomeric O-ring 1916 is preferably coated or treated to provide ahydrophilic surface (as discussed above for the surfaces of the cathodecontact ring) for contacting the wafer, and the elastomeric O-ring 1916is replaced as needed to ensure proper contact and seal to the wafer.Other bladder are useful in the electroplating processing cell accordingto the invention, such as the bladder system described in commonlyassigned and copending U.S. patent application Ser. No. 09/201,796entitled “iflatable Compliant Bladder Assembly”, filed on Nov. 30, 1998,which is hereby incorporated by reference in its entirety.

FIG. 12 is a second embodiment of the process head assembly having arotatable head assembly 2410. Preferably, a rotational actuator isdisposed on the cantilevered arm and attached to the head assembly torotate the head assembly during wafer processing. The rotatable headassembly 2410 is mounted onto a head assembly frame 2452. Thealternative head assembly frame 2452 and the rotatable head assembly2410 are mounted onto the mainframe similarly to the head assembly frame452 and head assembly 410 as shown in FIG. 6 and described above. Thehead assembly frame 2452 includes a mounting post 2454, a post cover2455, and a cantilever arm 2456. The mounting post 2454 is mounted ontothe body of the mainframe 214, and the post cover 2455 covers a topportion of the mounting post 2454. Preferably, the mounting post 454provides rotational movement (as indicated by arrow A1) with respect toa vertical axis along the mounting post to allow rotation of the headassembly frame 2452. The cantilever arm 2456 extends laterally from anupper portion of the mounting post 2454 and is pivotally connected tothe post cover 2455 at the pivot joint 2459. The rotatable head assembly2410 is attached to a mounting slide 2460 disposed at the distal end ofthe cantilever arm 2456. The mounting slide 2460 guides the verticalmotion of the head assembly 2410. A head lift actuator 2458 is disposedon top of the mounting slide 2460 to provide vertical displacement ofthe head assembly 2410.

The lower end of the cantilever arm 2456 is connected to the shaft 2453of a cantilever arm actuator 2457, such as a pneumatic cylinder or alead-screw actuator, mounted on the mounting post 2454. The cantileverarm actuator 2457 provides pivotal movement (as indicated by arrow A2)of the cantilever arm 2456 with respect to the joint 2459 between thecantilever arm 2456 and the post cover 2454. When the cantilever armactuator 2457 is retracted, the cantilever arm 2456 moves the headassembly 2410 away from the process kit 420 to provide the spacingrequired to remove and/or replace the process kit 420 from theelectroplating process cell 240. When the cantilever arm actuator 2457is extended, the cantilever arm 2456 moves the head assembly 2410 towardthe process kit 420 to position the wafer in the head assembly 2410 in aprocessing position.

The rotatable head assembly 2410 includes a rotating actuator 2464slideably connected to the mounting slide 2460. The shaft 2468 of thehead lift actuator 2458 is inserted through a lift guide 2466 attachedto the body of the rotating actuator 2464. Preferably, the shaft 2468 isa lead-screw type shaft that moves the lift guide (as indicated byarrows A3) between various vertical position. The rotating actuator 2464is connected to the wafer holder assembly 2450 through the shaft 2470and rotates the wafer holder assembly 2450 (as indicated by arrows A4).The wafer holder assembly 2450 includes a bladder assembly 2472, such asthe embodiments described above with respect to FIG. 10, and a cathodecontact ring 2474, such as the embodiments described above with respectto FIG. 9.

The rotation of the wafer during the electroplating process generallyenhances the deposition results. Preferably, the head assembly isrotated between about 2 rpm and about 20 rpm during the electroplatingprocess. The head assembly can also be rotated as the head assembly islowered to position the wafer in contact with the electrolyte in theprocess cell as well as when the head assembly is raised to remove thewafer from the electrolyte in the process cell. The head assembly ispreferably rotated at a high speed (i.e., >20 rpm) after the headassembly is lifted from the process cell to enhance removal of residualelectrolyte on the head assembly.

In one embodiment, the inventors have improved the uniformity of thedeposited film to within about 2% (i.e., maximum deviation of depositedfilm thickness is at about 2% of the average film thickness) whilestandard electroplating processes typically achieves uniformity at bestwithin about 5.5%. However, rotation of the head assembly is notnecessary to achieve uniform electroplating deposition in someinstances, particularly where the uniformity of electroplatingdeposition is achieved by adjusting the processing parameters, such asthe electrolyte chemistry, electrolyte flow and other parameters.

Referring back to FIG. 6, a cross sectional view of an electroplatingprocess cell 400, the wafer holder assembly 450 is positioned above theprocess kit 420. The process kit 420 generally comprises a bowl 430, acontainer body 472, an anode assembly 474 and a filter 476. Preferably,the anode assembly 474 is disposed below the container body 472 andattached to a lower portion of the container body 472, and the filter476 is disposed between the anode assembly 474 and the container body472. The container body 472 is preferably a cylindrical body comprisedof an electrically insulative material, such as ceramics, plastics,plexiglass (acrylic), lexane, PVC, CPVC, and PVDF. Alternatively, thecontainer body 472 can be made from a metal, such as stainless steel,nickel and titanium, which is coated with an insulating layer, such asTeflonTM, PVDF, plastic, rubber and other combinations of materials thatdo not dissolve in the electrolyte and can be electrically insulatedfrom the electrodes (i.e., the anode and cathode of the electroplatingsystem). The container body 472 is preferably sized and adapted toconform to the wafer plating surface and the shape of the of a waferbeing processed through the system, typically circular or rectangular inshape. One preferred embodiment of the container body 472 comprises acylindrical ceramic tube having an inner diameter that has about thesame dimension as or slightly larger than the wafer diameter. Theinventors have discovered that the rotational movement typicallyrequired in typical electroplating systems is not required to achieveuniform plating results when the size of the container body conforms toabout the size of the wafer plating surface.

An upper portion of the container body 472 extends radially outwardly toform an annular weir 478. The weir 478 extends over the inner wall 446of the electrolyte collector 440 and allows the electrolyte to flow intothe electrolyte collector 440. The upper surface of the weir 478preferably matches the lower surface of the cathode contact ring 466.Preferably, the upper surface of the weir 478 includes an inner annularflat portion 480, a middle inclined portion 482 and an outer declinedportion 484. When a wafer is positioned in the processing position, thewafer plating surface is positioned above the cylindrical opening of thecontainer body 472, and a gap for electrolyte flow is formed between thelower surface of the cathode contact ring 466 and the upper surface ofthe weir 478. The lower surface of the cathode contact ring 466 isdisposed above the inner flat portion 480 and the middle inclinedportion of the weir 478. The outer declined portion 484 is slopeddownwardly to facilitate flow of the electrolyte into the electrolytecollector 440.

A lower portion of the container body 472 extends radially outwardly toform a lower annular flange 486 for securing the container body 472 tothe bowl 430. The outer dimension (i.e., circumference) of the annularflange 486 is smaller than the dimensions of the opening 444 and theinner circumference of the electrolyte collector 440 to allow removaland replacement of the process kit 420 from the electroplating processcell 400. Preferably, a plurality of bolts 488 are fixedly disposed onthe annular flange 486 and extend downwardly through matching bolt holeson the bowl 430. A plurality of removable fastener nuts 490 secure theprocess kit 420 onto the bowl 430. A seal 487, such as an elastomerO-ring, is disposed between container body 472 and the bowl 430 radiallyinwardly from the bolts 488 to prevent leaks from the process kit 420.The nuts/bolts combination facilitates fast and easy removal andreplacement of the components of the process kit 420 during maintenance.

Preferably, the filter 476 is attached to and completely covers thelower opening of the container body 472, and the anode assembly 474 isdisposed below the filter 476. A spacer 492 is disposed between thefilter 476 and the anode assembly 474. Preferably, the filter 476, thespacer 492, and the anode assembly 474 are fastened to a lower surfaceof the container body 472 using removable fasteners, such as screwsand/or bolts. Alternatively, the filter 476, the spacer 492, and theanode assembly 474 are removably secured to the bowl 430. The filter 476preferably comprises a ceramic diffluser that also serves to control theelectrolyte flow pattern toward the substrate plating surface.

The anode assembly 474 preferably comprises a consumable anode thatserves as a metal source in the electrolyte. Alternatively, the anodeassembly 474 comprises a non-consumable anode, and the metal to beelectroplated is supplied within the electrolyte from the electrolytereplenishing system 220. As shown in FIG. 6, the anode assembly 474 is aself-enclosed module having a porous anode enclosure 494 preferably madeof the same metal as the metal to be electroplated, such as copper.Alternatively, the anode enclosure 494 is made of porous materials, suchas ceramics or polymeric membranes. A soluble metal 496, such as highpurity copper for electro-chemical deposition of copper, is disposedwithin the anode enclosure 494. The soluble metal 496 preferablycomprises metal particles, wires or a perforated sheet. The porous anodeenclosure 494 also acts as a filter that keeps the particulatesgenerated by the dissolving metal within the anode enclosure 494. Ascompared to a non-consumable anode, the consumable (i.e., soluble) anodeprovides gas-generation-free electrolyte and minimizes the need toconstantly replenish the metal in the electrolyte.

An anode electrode contact 498 is inserted through the anode enclosure494 to provide electrical connection to the soluble metal 496 from apower supply. Preferably, the anode electrode contact 498 is made from aconductive material that is insoluble in the electrolyte, such astitanium, platinum and platinum-coated stainless steel. The anodeelectrode contact 498 extends through the bowl 430 and is connected toan electrical power supply. Preferably, the anode electrical contact 498includes a threaded portion 497 for a fastener nut 499 to secure theanode electrical contact 498 to the bowl 430, and a seal 495, such as aelastomer washer, is disposed between the fastener nut 499 and the bowl430 to prevent leaks from the process kit 420.

The bowl 430 generally comprises a cylindrical portion 502 and a bottomportion 504. An upper annular flange 506 extends radially outwardly fromthe top of the cylindrical portion 502. The upper annular flange 506includes a plurality of holes 508 that matches the number of bolts 488from the lower annular flange 486 of the container body 472. To securethe upper annular flange 506 of the bowl 430 and the lower annularflange 486 of the container body 472, the bolts 488 are inserted throughthe holes 508, and the fastener nuts 490 are fastened onto the bolts488. Preferably, the outer dimension (i.e., circumference) of the upperannular flange 506 is about the same as the outer dimension (ie.,circumference) of the lower annular flange 486. Preferably, the lowersurface of the upper annular flange 506 of the bowl 430 rests on asupport flange of the mainframe 214 when the process kit 420 ispositioned on the mainframe 214.

The inner circumference of the cylindrical portion 502 accommodates theanode assembly 474 and the filter 476. Preferably, the outer dimensionsof the filter 476 and the anode assembly 474 are slightly smaller thanthe inner dimension of the cylindrical portion 502 to force asubstantial portion of the electrolyte to flow through the anodeassembly 474 first before flowing through the filter 476. The bottomportion 504 of the bowl 430 includes an electrolyte inlet 510 thatconnects to an electrolyte supply line from the electrolyte replenishingsystem 220. Preferably, the anode assembly 474 is disposed about amiddle portion of the cylindrical portion 502 of the bowl 430 to providea gap for electrolyte flow between the anode assembly 474 and theelectrolyte inlet 510 on the bottom portion 504.

The electrolyte inlet 510 and the electrolyte supply line are preferablyconnected by a releasable connector that facilitates easy removal andreplacement of the process kit 420. When the process kit 420 needsmaintenance, the electrolyte is drained from the process kit 420, andthe electrolyte flow in the electrolyte supply line is discontinued anddrained. The connector for the electrolyte supply line is released fromthe electrolyte inlet 510, and the electrical connection to the anodeassembly 474 is also disconnected. The head assembly 410 is raised orrotated to provide clearance for removal of the process kit 420. Theprocess kit 420 is then removed from the mainframe 214, and a new orreconditioned process kit is replaced into the mainframe 214.

Alternatively, the bowl 430 can be secured onto the support flange ofthe mainframe 214, and the container body 472 along with the anode andthe filter are removed for maintenance. In this case, the nuts securingthe anode assembly 474 and the container body 472 to the bowl 430 areremoved to facilitate removal of the anode assembly 474 and thecontainer body 472. New or reconditioned anode assembly 474 andcontainer body 472 are then replaced into the mainframe 214 and securedto the bowl 430.

FIG. 11 is a cross sectional view of an encapsulated anode. Theencapsulated anode 2000 includes a permeable anode enclosure thatfilters or traps “anode sludge” or particulates generated as the metalis dissolved from the anode plate 2004. As shown in FIG. 11, theconsumable anode plate 2004 comprises a solid piece of copper,preferably, high purity, oxygen free copper, enclosed in a hydrophilicanode encapsulation membrane 2002. The anode plate 2004 is secured andsupported by a plurality of electrical contacts or feed-throughs 2006that extend through the bottom of the bowl 430. The electrical contactsor feed-throughs 2006 extend through the anode encapsulation membrane2002 into the bottom surface of the anode plate 2004. The flow of theelectrolyte is indicated by the arrows A from the electrolyte inlet 510disposed at the the bottom of the bowl 430 through the gap between theanode and the bowl sidewall. The electrolyte also flows through theanode encapsulation membrane 2002 by permeation into and out of the gapbetween the anode encapsulation membrane and the anode plate, asindicated by the arrows B. Preferably, the anode encapsulation membrane2002 comprises a hydrophilic porous membrane, such as a modifiedpolyvinyllidene fluoride membrane, having porosity between about 60% and80%, more preferably about 70%, and pore sizes between about 0.025 μmand about 1 μm, more preferably between about 0.1 μm and about 0.2 μm.One example of a hydrophilic porous membrane is the Durapore HydrophilicMembrane, available from Millipore Corporation, located in Bedford,Mass. As the electrolyte flows through the encapsulation membrane, anodesludge and particulates generated by the dissolving anode are filteredor trapped by the encapsulation membrane. Thus, the encapsulationmembranes improve the purity of the electrolyte during theelectroplating process, and defect formations on the substrate duringthe electroplating process caused by anode sludge and contaminantparticulates are significantly reduced. Other anode designs are usefulin the electroplating processing cell according to the invention, suchas the anode designs described in commonly assigned and copending U.S.patent application Ser. No. 09/289,074, entitled “Electro-ChemicalDeposition System”, filed on Apr. 8, 1999, which is hereby incorporatedby reference in its entirety.

FIG. 7 is a schematic diagram of an electrolyte replenishing system 220.The electrolyte replenishing system 220 provides the electrolyte to theelectroplating process cells for the electroplating process. Theelectrolyte replenishing system 220 generally comprises a mainelectrolyte tank 602, a dosing module 603, a filtration module 605, achemical analyzer module 616, and an electrolyte waste disposal system622 connected to the analyzing module 616 by an electrolyte waste drain620. One or more controllers control the composition of the electrolytein the main tank 602 and the operation of the electrolyte replenishingsystem 220. Preferably, the controllers are independently operable butintegrated with the control system 222 of the electroplating systemplatform 200.

The main electrolyte tank 602 provides a reservoir for electrolyte andincludes an electrolyte supply line 612 that is connected to each of theelectroplating process cells through one or more fluid pumps 608 andvalves 607. A heat exchanger 624 or a heater/chiller disposed in thermalconnection with the main tank 602 controls the temperature of theelectrolyte stored in the main tank 602. The heat exchanger 624 isconnected to and operated by the controller 610.

The dosing module 603 is connected to the main tank 602 by a supply lineand includes a plurality of source tanks 606, or feed bottles, aplurality of valves 609, and a controller 611. The source tanks 606contain the chemicals needed for composing the electrolyte and typicallyinclude a deionized water source tank and copper sulfate (CuSO₄) sourcetank for composing the electrolyte. Other source tanks 606 may containhydrogen sulfate (H₂SO₄), hydrogen chloride (HCl) and various additivessuch as glycol. Each source tank is preferably color coded and fittedwith a unique mating outlet connector adapted to connect to a matchinginlet connector in the dosing module. By color coding the source tanksand fitting the source tanks with unique connectors, errors caused byhuman operators when exchanging or replacing the source tanks aresignificantly reduced.

The deionized water source tank preferably also provides deionized waterto the system for cleaning the system during maintenance. The valves 609associated with each source tank 606 regulate the flow of chemicals tothe main tank 602 and may be any of numerous commercially availablevalves such as butterfly valves, throttle valves and the like.Activation of the valves 609 is accomplished by the controller 611 whichis preferably connected to the system control 222 to receive signalstherefrom.

The electrolyte filtration module 605 includes a plurality of filtertanks 604. An electrolyte return line 614 is connected between each ofthe process cells and one or more filter tanks 604. The filter tanks 604remove the undesired contents in the used electrolyte before returningthe electrolyte to the main tank 602 for re-use. The main tank 602 isalso connected to the filter tanks 604 to facilitate re-circulation andfiltration of the electrolyte in the main tank 602. By re-circulatingthe electrolyte from the main tank 602 through the filter tanks 604, theundesired contents in the electrolyte are continuously removed by thefilter tanks 604 to maintain a consistent level of purity. Additionally,re-circulating the electrolyte between the main tank 602 and thefiltration module 605 allows the various chemicals in the electrolyte tobe thoroughly mixed.

The electrolyte replenishing system 220 also includes a chemicalanalyzer module 616 that provides real-time chemical analysis of thechemical composition of the electrolyte. The analyzer module 616 isfluidly coupled to the main tank 602 by a sample line 613 and to thewaste disposal system 622 by an outlet line 621. The analyzer module 616generally comprises at least one analyzer and a controller to operatethe analyzer. The number of analyzers required for a particularprocessing tool depends on the composition of the electrolyte. Forexample, while a first analyzer may be used to monitor theconcentrations of organic substances, a second analyzer is needed forinorganic chemicals. In the specific embodiment shown in FIG. 7 thechemical analyzer module 616 comprises an auto titration analyzer 615and a cyclic voltametric stripper (CVS) 617. Both analyzers arecommercially available from various suppliers. An auto titrationanalyzer which may be used to advantage is available from Parker Systemsand a cyclic voltametric stripper is available from ECI. The autotitration analyzer 615 determines the concentrations of inorganicsubstances such as copper chloride and acid. The CVS 617 determines theconcentrations of organic substances such as the various additives whichmay be used in the electrolyte and by-products resulting from theprocessing which are returned to the main tank 602 from the processcells.

Preferably, the analyzers include standards and calibration schemes thatfacilitates the controller to compensate for the drifts in measurementsas the electrodes or sensors in the analyzers become corroded due torepeated use. The standards and calibration schemes are preferablygrouped according to the substances being analyzed by the analyzer. Forexample, the auto titration analyzer 615 includes standards andcalibration schemes for the inorganic substances, and the CVS 617includes standards and calibration schemes for the organic substances.For example, as shown in Table 1, three standards are provided for ananalysis of copper and chloride contents in the electrolyte.

TABLE 1 Standards for copper and chloride contents Copper ChlorideStandard 1 (low) 40 g/l 40 ppm Standard 2 (medium) 50 g/l 70 ppmStandard 3(high) 60 g/l 100 ppm

The analyzer uses the standards to determine the deviation ormeasurement drift of the electrode or sensor as the electrode or sensorfor the analyzer for the copper and chloride contents becomes corrodedwith repeated use. By interpolating a linear relationship between theknown contents in the standards and the measurement by the analyzer, theanalyzer becomes calibrated to provide accurate analysis of thesubstances in the electrolyte sample. The measured data from theelectrolyte sample is compensated for the measurement drifts of theelectrodes or sensors to provide accurate measurements. By usingstandards and calibration schemes, the invention provides accuratereal-time, on-line analysis of the electrolyte and facilitates aclosed-loop analysis that can be performed with an analyzer attached tothe system. The invention also extends the useful life of the electrodesor sensors and decreases the frequency of system interruptions due toreplacement of these components.

The analyzer module shown FIG. 7 is merely illustrative. In anotherembodiment each analyzer may be coupled to the main electrolyte tank bya separate supply line and be operated by separate controllers. Personsskilled in the art will recognize other embodiments.

In operation, a sample of electrolyte is flowed to the analyzer module616 via the sample line 613. Although the sample may be takenperiodically, preferably a continuous flow of electrolyte is maintainedto the analyzer module 616. A portion of the sample is delivered to theauto titration analyzer 615 and a portion is delivered to the CVS 617for the appropriate analysis. The controller 619 initiates commandsignals to operate the analyzers 615, 617 in order to generate data. Theinformation from the chemical analyzers 615, 617 is then communicated tothe control system 222. The control system 222 processes the informationand transmits signals which include user-defined chemical dosageparameters to the dosing controller 611. The received information isused to provide real-time adjustments to the source chemicalreplenishment rates by operating one or more of the valves 609 therebymaintaining a desired, and preferably constant, chemical composition ofthe electrolyte throughout the electroplating process. The wasteelectrolyte from the analyzer module is then flowed to the wastedisposal system 622 via the outlet line 621.

Although a preferred embodiment utilizes real-time monitoring andadjustments of the electrolyte, various alternatives may be employedaccording to the present invention. For example, the dosing module 603may be controlled manually by an operator observing the output valuesprovided by the chemical analyzer module 616. Preferably, the systemsoftware allows for both an automatic real-time adjustment mode as wellas an operator (manual) mode. Further, although multiple controllers areshown in FIG. 7, a single controller may be used to operate variouscomponents of the system such as the chemical analyzer module 616, thedosing module 603, and the heat exchanger 624. Other embodiments will beapparent to those skilled in the art.

The electrolyte replenishing system 220 also includes an electrolytewaste drain 620 connected to an electrolyte waste disposal system 622for safe disposal of used electrolytes, chemicals and other fluids usedin the electroplating system. Preferably, the electroplating cellsinclude a direct line connection to the electrolyte waste drain 620 orthe electrolyte waste disposal system 622 to drain the electroplatingcells without returning the electrolyte through the electrolytereplenishing system 220. The electrolyte replenishing system 220preferably also includes a bleed off connection to bleed off excesselectrolyte to the electrolyte waste drain 620.

Preferably, the electrolyte replenishing system 220 also includes one ormore degasser modules 630 adapted to remove undesirable gases from theelectrolyte. The degasser module generally comprises a membrane thatseparates gases from the fluid passing through the degasser module and avacuum system for removing the released gases. The degasser modules 630are preferably placed in line on the electrolyte supply line 612adjacent to the process cells 240. The degasser modules 630 arepreferably positioned as close as possible to the process cells 240 sothat most of the gases from the electrolyte replenishing system areremoved by the degasser modules before the electrolyte enters theprocess cells. Preferably, each degasser module 630 includes two outletsto supply degassed electrolyte to the two process cells 240 of eachprocessing station 218. Alternatively, a degasser module 630 is providedfor each process cell. The degasser modules can be placed at many otheralternative positions. For example, the degasser module can be placed atother positions in the electrolyte replenishing system, such as alongwith the filter section or in a closed-loop system with the main tank orwith the processing cell. As another example, one degasser module isplaced in line with the electrolyte supply line 612 to provide degassedelectrolyte to all of the process cells 240 of the electrochemicaldeposition system. Additionally, a separate degasser module ispositioned in-line or in a closed-loop with the deionized water supplyline and is dedicated for removing oxygen from the deionized watersource. Because deionized water is used to rinse the processedsubstrates, free oxygen gases are preferable removed from the deionizedwater before reaching the SRD modules so that the electroplated copperis less likely to become oxidized by the rinsing process. Degassermodules are well known in the art and commercial embodiments aregenerally available and adaptable for use in a variety of applications.A commercially available degasser module is available from MilliporeCorporation, located in Bedford, Massachusettes.

One embodiment of the degasser module 630, as shown in FIG. 13a,includes a hydrophobic membrane 632 having a fluid (i.e., electrolyte)passage 634 on one side of the membrane 632 and a vacuum system 636disposed on the opposite side of the membrane. The enclosure 638 of thedegasser module includes an inlet 640 and one or more outlets 642. Asthe electrolyte passes through the degasser module 630, the gases andother micro-bubbles in the electrolyte are separated from theelectrolyte through the hydrophobic membrane and removed by the vacuumsystem. Another embodiment of the degasser module 630′, as shown in FIG.13b, includes a tube of hydrophobic membrane 632′ and a vacuum system636 disposed around the tube of hydrophobic membrane 632′. Theelectrolyte is introduced inside the tube of hydrophobic membrane, andas the electrolyte passes through the fluid passage 634 in the tube,gases and other micro-bubbles in the electrolyte are separated from theelectrolyte through the tube of hydrophobic membrane 632′ and removed bythe vacuum system 636 surrounding the tube. More complex designs ofdegasser modules are contemplated by the invention, including designshaving serpentine paths of the electrolyte across the membrane and othermulti-sectioned designs of degasser modules.

Although not shown in FIG. 7, the electrolyte replenishing system 220may include a number of other components. For example, the electrolytereplenishing system 220 preferably also includes one or more additionaltanks for storage of chemicals for a wafer cleaning system, such as theSRD station. Double-contained piping for hazardous material connectionsmay also be employed to provide safe transport of the chemicalsthroughout the system. Optionally, the electrolyte replenishing system220 includes connections to additional or external electrolyteprocessing system to provide additional electrolyte supplies to theelectroplating system.

FIG. 8 is a cross sectional view of a rapid thermal anneal chamberaccording to the invention. The rapid thermal anneal (RTA) chamber 211is preferably connected to the loading station 210, and substrates aretransferred into and out of the RTA chamber 211 by the loading stationtransfer robot 228. The electroplating system, as shown in FIGS. 2 and3, preferably comprises two RTA chambers 211 disposed on opposing sidesof the loading station 210, corresponding to the symmetric design of theloading station 210. Thermal anneal process chambers are generally wellknown in the art, and rapid thermal anneal chambers are typicallyutilized in substrate processing systems to enhance the properties ofthe deposited materials. The invention contemplates utilizing a varietyof thermal anneal chamber designs, including hot plate designs and heatlamp designs, to enhance the electroplating results. One particularthermal anneal chamber useful for the present invention is the WxZchamber available from Applied materials, Inc., located in Santa Clara,Calif. Although the invention is described using a hot plate rapidthermal anneal chamber, the invention contemplates application of otherthermal anneal chambers as well.

The RTA chamber 211 generally comprises an enclosure 902, a heater plate904, a heater 907 and a plurality of substrate support pins 906. Theenclosure 902 includes a base 908, a sidewall 910 and a top 912.Preferably, a cold plate 913 is disposed below the top 912 of theenclosure. Alternatively, the cold plate is integrally formed as part ofthe top 912 of the enclosure. Preferably, a reflector insulator dish 914is disposed inside the enclosure 902 on the base 908. The reflectorinsulator dish 914 is typically made from a material such as quartz,alumina, or other material that can withstand high temperatures (ie.,greater than about 500° C.), and act as a thermal insulator between theheater 907 and the enclosure 902. The dish 914 may also be coated with areflective material, such as gold, to direct heat back to the heaterplate 906.

The heater plate 904 preferably has a large mass compared to thesubstrate being processed in the system and is preferably fabricatedfrom a material such as silicon carbide, quartz, or other materials thatdo not react with any ambient gases in the RTA chamber 211 or with thesubstrate material. The heater 907 typically comprises a resistiveheating element or a conductive/radiant heat source and is disposedbetween the heated plate 906 and the reflector insulator dish 914. Theheater 907 is connected to a power source 916 which supplies the energyneeded to heat the heater 907. Preferably, a thermocouple 920 isdisposed in a conduit 922, disposed through the base 908 and dish 914,and extends into the heater plate 904. The thermocouple 920 is connectedto a controller (ie., the system controller described below) andsupplies temperature measurements to the controller. The controller thenincreases or decreases the heat supplied by the heater 907 according tothe temperature measurements and the desired anneal temperature.

The enclosure 902 preferably includes a cooling member 918 disposedoutside of the enclosure 902 in thermal contact with the sidewall 910 tocool the enclosure 902. Alternatively, one or more cooling channels (notshown) are formed within the sidewall 910 to control the temperature ofthe enclosure 902. The cold plate 913 disposed on the inside surface ofthe top 912 cools a substrate that is positioned in close proximity tothe cold plate 913.

The RTA chamber 211 includes a slit valve 922 disposed on the sidewall910 of the enclosure 902 for facilitating transfers of substrates intoand out of the RTA chamber. The slit valve 922 selectively seals anopening 924 on the sidewall 910 of the enclosure that communicates withthe loading station 210. The loading station transfer robot 228 (seeFIG. 2) transfers substrates into and out of the RTA chamber through theopening 924.

The substrate support pins 906 preferably comprise distally taperedmembers constructed from quartz, aluminum oxide, silicon carbide, orother high temperature resistant materials. Each substrate support pin906 is disposed within a tubular conduit 926, preferably made of a heatand oxidation resistant material, that extends through the heater plate904. The substrate support pins 906 are connected to a lift plate 928for moving the substrate support pins 906 in a uniform manner. The liftplate 928 is attached to an to an actuator 930, such as a stepper motor,through a lift shaft 932 that moves the lift plate 928 to facilitatepositioning of a substrate at various vertical positions within the RTAchamber. The lift shaft 932 extends through the base 908 of theenclosure 902 and is sealed by a sealing flange 934 disposed around theshaft.

To transfer a substrate into the RTA chamber 211, the slit valve 922 isopened, and the loading station transfer robot 228 extends its robotblade having a substrate positioned thereon through the opening 924 intothe RTA chamber. The robot blade of the loading station transfer robot228 positions the substrate in the RTA chamber above the heater plate904, and the substrate support pins 906 are extended upwards to lift thesubstrate above the robot blade. The robot blade then retracts out ofthe RTA chamber, and the slit valve 922 closes the opening. Thesubstrate support pins 906 are then retracted to lower the substrate toa desired distance from the heater plate 904. Optionally, the substratesupport pins 906 may retract fully to place the substrate in directcontact with the heater plate.

Preferably, a gas inlet 936 is disposed through the sidewall 910 of theenclosure 902 to allow selected gas flow into the RTA chamber 211 duringthe anneal treatment process. The gas inlet 936 is connected to a gassource 938 through a valve 940 for controlling the flow of the gas intothe RTA chamber 211. A gas outlet 942 is preferably disposed at a lowerportion of the sidewall 910 of the enclosure 902 to exhaust the gases inthe RTA chamber and is preferably connected to a relief/check valve 944to prevent backstreaming of atmosphere from outside of the chamber.Optionally, the gas outlet 942 is connected to a vacuum pump (not shown)to exhaust the RTA chamber to a desired vacuum level during an annealtreatment.

According to the invention, a substrate is annealed in the RTA chamber211 after the substrate has been electroplated in the electroplatingcell and cleaned in the SRD station. Preferably, the RTA chamber 211 ismaintained at about atmospheric pressure, and the oxygen content insidethe RTA chamber 211 is controlled to less than about 100 ppm during theanneal treatment process. Preferably, the ambient environment inside theRTA chamber 211 comprises nitrogen (N₂) or a combination of nitrogen(N₂) and less than about 4% hydrogen (H₂), and the ambient gas flow intothe RTA chamber 211 is maintained at greater than 20 liters/min tocontrol the oxygen content to less than 100 ppm. The electroplatedsubstrate is preferably annealed at a temperature between about 200° C.and about 450° C. for between about 30 seconds and 30 minutes, and morepreferably, between about 250° C. and about 400° C. for between about 1minute and 5 minutes. Rapid thermal anneal processing typically requiresa temperature increase of at least 50° C. per second. To provide therequired rate of temperature increase for the substrate during theanneal treatment, the heater plate is preferably maintained at betweenabout 350° C. and about 450° C., and the substrate is preferablypositioned at between about 0 mm (i.e., contacting the heater plate) andabout 20 mm from the heater plate for the duration of the annealtreatment process. Preferably, a control system 222 controls theoperation of the RTA chamber 211, including maintaining the desiredambient environment in the RTA chamber and the temperature of the heaterplate.

After the anneal treatment process is completed, the substrate supportpins 906 lift the substrate to a position for transfer out of the RTAchamber 211. The slit valve 922 opens, and the robot blade of theloading station transfer robot 228 is extended into the RTA chamber andpositioned below the substrate. The substrate support pins 906 retractto lower the substrate onto the robot blade, and the robot blade thenretracts out of the RTA chamber. The loading station transfer robot 228then transfers the processed substrate into the cassette 232 for removalout of the electroplating processing system. (see FIGS. 2 and 3).

Referring back to FIG. 2, the electroplating system platform 200includes a control system 222 that controls the functions of eachcomponent of the platform. Preferably, the control system 222 is mountedabove the mainframe 214 and comprises a programmable microprocessor. Theprogrammable microprocessor is typically programmed using a softwaredesigned specifically for controlling all components of theelectroplating system platform 200. The control system 222 also provideselectrical power to the components of the system and includes a controlpanel 223 that allows an operator to monitor and operate theelectroplating system platform 200. The control panel 223, as shown inFIG. 2, is a stand-alone module that is connected to the control system222 through a cable and provides easy access to an operator. Generally,the control system 222 coordinates the operations of the loading station210, the RTA chamber 211, the SRD station 212, the mainframe 214 and theprocessing stations 218. Additionally, the control system 222coordinates with the controller of the electrolyte replenishing system220 to provide the electrolyte for the electroplating process.

The following is a description of a typical wafer electroplating processsequence through the electroplating system platform 200 as shown in FIG.2. The process sequence described below is exemplary of various otherprocess sequence or combination that can be performed utilizing theelectro-chemical deposition system according to the invention. A wafercassette containing a plurality of wafers is loaded into the wafercassette receiving areas 224 in the loading station 210 of theelectroplating system platform 200. A loading station transfer robot 228picks up a wafer from a wafer slot in the wafer cassette and places thewafer in the wafer orientor 230. The wafer orientor 230 determines andorients the wafer to a desired orientation for processing through thesystem. The loading station transfer robot 228 then transfers theoriented wafer from the wafer orientor 230 and positions the wafer inone of the wafer slots in the wafer pass-through cassette 238 in the SRDstation 212. The mainframe transfer robot 242 picks up the wafer fromthe wafer pass-through cassette 238 and secures the wafer on the flipperrobot end effector. The mainframe transfer robot 242 transfers the waferto the EDP cell 3010, and a seed layer repair process is performedutilizing electroless deposition.

After the seed layer repair process, the mainframe transfer robottransfers the wafer to the processing cell 240 for the electroplatingprocess. The flipper robot end effector 2404 rotates and positions thewafer face down in the wafer holder assembly 450. The wafer ispositioned below the wafer holder 464 but above the cathode contact ring466. The flipper robot end effector 2404 then releases the wafer toposition the wafer into the cathode contact ring 466. The wafer holder464 moves toward the wafer and the vacuum chuck secures the wafer on thewafer holder 464. The bladder assembly 470 on the wafer holder assembly450 exerts pressure against the wafer backside to ensure electricalcontact between the wafer plating surface and the cathode contact ring466.

The head assembly 452 is lowered to a processing position above theprocess kit 420. At this position the wafer is below the upper plane ofthe weir 478 and contacts the electrolyte contained in the process kit420. The power supply is activated to supply electrical power (ie.,voltage and current) to the cathode and the anode to enable theelectroplating process. The electrolyte is typically continually pumpedinto the process kit during the electroplating process. The electricalpower supplied to the cathode and the anode and the flow of theelectrolyte are controlled by the control system 222 to achieve thedesired electroplating results. Preferably, the head assembly is rotatedas the head assembly is lowered and also during the electroplatingprocess.

After the electroplating process has been completed, the head assembly410 raises the wafer holder assembly and removes the wafer from theelectrolyte. Preferably, the head assembly is rotated for a period oftime to enhance removal of residual electrolyte from the wafer holderassembly. The vacuum chuck and the bladder assembly of the wafer holderthen release the wafer from the wafer holder, and the wafer holder israised to allow the flipper robot end effector 2404 to pick up theprocessed wafer from the cathode contact ring. The flipper robot endeffector 2404 is moved to a position above the backside of the processedwafer in the cathode contact ring and picks up the wafer using thevacuum suction gripper on the flipper robot end effector. The mainframetransfer robot retracts the flipper robot end effector with the waferout of the processing cell 240 and the flipper robot end effector flipsthe wafer from a face-down position to a face-up position.

The wafer is then transferred into the EBR/SRD module 2200. The EBR/SRDwafer support lifts the wafer, and the mainframe transfer robot retractsout of the EBR/SRD module 2200. The wafer is positioned onto the vacuumwafer holder in the EBR/SRD cell, and an edge bead removal process isperformed, as described in detail above, to remove excess deposition atthe edge portion of the wafer. The wafer is then cleaned using aspin-rinse-dry process in the EBR/SRD module using deionized water or acombination of deionized water and a cleaning fluid as described indetail above. The wafer is then positioned for transfer out of theEBR/SRD module.

The loading station transfer robot 228 picks up the wafer from theEBR/SRD module 2200 and transfers the processed wafer into the RTAchamber 211 for an anneal treatment process to enhance the properties ofthe deposited materials. The annealed wafer is then transferred out ofthe RTA chamber 211 by the loading station robot 228 and placed backinto the wafer cassette for removal from the electroplating system. Theabove-described sequence can be carried out for a plurality of waferssubstantially simultaneously in the electroplating system platform 200of the present invention. Also, the electroplating system according tothe invention can be adapted to provide multi-stack wafer processing.

While the foregoing is directed to the preferred embodiment of thepresent invention, other and further embodiments of the invention may bedevised without departing from the basic scope thereof. The scope of theinvention is determined by the claims which follow.

What is claimed is:
 1. An electro-chemical deposition system,comprising: a) a mainframe having a mainframe wafer transfer robot; b) aloading station disposed in connection with the mainframe; c) one ormore processing cells disposed in connection with the mainframe; d) anelectrolyte supple fluidly connected to the one or more processingcells; and e) a seed layer repair station disposed on the mainframe. 2.The system of claim 1 wherein the seed layer repair station comprises anelectroless deposition cell.
 3. The system of claim 1, furthercomprising: a system controller for controlling an electrochemicaldeposition process.
 4. The system of claim 3, further comprising: anedge bead removal/spin-rinse-dry (EBR/SRD) station disposed on the mainframe adjacent the loading station.
 5. The system of claim 4, furthercomprising: a thermal anneal chamber disposed in connection with theloading station.
 6. The system of claim 1 wherein the mainframe includesa base having a protective coating.
 7. The system of claim 6 wherein thecoating comprises ethylene-chloro-tri-fluoro-ethaylene (ECTFE).
 8. Anelectrochemical deposition system, comprising: a) a mainframe having amainframe wafer transfer robot; b) a loading station disposed inconnection with the mainframe; c) one or more processing cells disposedin connection with the mainframe; and d) an electrolyte supply fluidlyconnected to the one or more processing cells, wherein the electrolytesupply comprises: i) a main tank connected through a pump to theprocessing cells; ii) one or more filter tanks connected to the maintank; and iii) one or more source tanks connected to the main tank. 9.The system of claim 8, further comprising an analyzer disposed in aclosed loop system with the electrolyte supply.
 10. The system of claim9 wherein the analyzer includes one or more standards and one or morecalibration schemes.